一句话一个点

cat a|python -m json.tool

HBase don't split a single row.

JVM中CMS全拼concurrent (low pause time) garbage collector (also known as CMS)

mvn clean install -DskipTests

fdisk -l

netstat -tunlp

netstat -nlp

rpm -ivh XXX.rpm

du -h --max-depth=1 work/testing

hadoop jar XX.jar -libjars protobuf-java-2.4.0a.jar /log

 ./hadoop fs -copyFromLocal local.txt /remote.txt 

 

ps axu|grep udpcopy

nohup sh XXX.sh & 真正的后台执行

 

tcppump

 

yum -y erase libstdc++.so.5

hadoop balancer -threshold 10 >>balancer.log 2>&1 &

git clone https://github.com/openstack-dev/devstack.git -b stable grizzly

ll /lib/libc.so.6

 

所有运行的程序同时能打开的文件总数,服务器支持的最大并发

cat /proc/sys/fs/file-max

 

G:\sts\protobuf\message>protoc -I=G:\sts\protobuf\message --java_out=G:\sts\prot
obuf\src\main\java G:\sts\protobuf\message\addressbook.proto

netstat -ntl  | grep 13091 查看使用的

netstat -an | grep :13091 查看去监听的

iftop -i bond0 -n 查看带宽利用

sed s/6348/6319/ redis_6348.conf > redis_6319.conf 字符替换

echo 3 > /proc/sys/vm/drop_caches释放缓存

echo 0 > /proc/sys/vm/drop_caches马上回复，否则影响性能

-Dsun.awt.disablegrab=true

find a specified string in all the java files:

find . -name '*.java' | xargs grep -l 'string'

or grep -r "String" --include=*.java .

if there are any filename or directories have spaces then the safest way to do this is:

find . -name '*.java' -print0 | xargs -0 grep -l 'string'

grep -i -r -n --include="*.f" gendetl_start_js .

ls | grep -v unwanted | xargs tail -f (tail -f * but unwanted files)

mvn -Dtest=org.package.class#method test run unit test for one class and method

# check database size

SELECT table_schema                                        "DB Name",     Round(Sum(data_length + index_length) / 1024 / 1024 / 1024, 1) "DB Size in GB"  FROM   information_schema.tables  GROUP  BY table_schema;

ubuntu 中文输入法 推荐第一种Google 中文输入法

 http://ubuntuhandbook.org/index.php/2016/07/2-best-chinese-pinyin-im-ubuntu-16-04/

wmic process where caption="KDGTemplateDesigner.exe" get caption,commandline /value

mvn spring-boot:run -Dspring-boot.run.jvmArguments="-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=5005"